JOURNAL 



O F 



NATURAL PHILOSOPHY, CHEMISTRY, 



AKD 



THE ARTS. 



DECEMBER 1800. 



ARTICLE I. 



On the Number of the Primitive Colorific Rays in Solar Light. By the Rev. Matthev 

 Youtra, D. D. S F. T. C. D. isf M. R. I. A. 



HE opinion that there are but three primitive colours has been maintained by M. du 

 Fay, and after him by Father Caftelli. See Montucla, Vol. I. p. 630. ; but they and all " 

 others who hold the fame doiEtrine, defend it merely on the principles of a painter, who 

 (hews how with thefe three colours on his pallet, he can compound all others ; for with 

 red and yellow he can form an orange colour; with blue and yellow he forms green; and 

 with blue and red he forms indigo and violet ; and thus having compounded the feven prif- 

 matic colours, It iS manifeft that all other colours, with their diiFerent gradations, can be 

 formed from them likewife. But i^\s pharmaceutical argument is by no means fufficient to 

 fatisfy us as to the real compofition of folar light. 



<' Light, in refrafting, is dccompofed into feven rays, red, orange, yellow, green, 

 «' blue, indigo and violet. It has been fuppofed," fays Fourcroy, " that three of thefe 

 " colours, the red, yellow, and blue, were fimple ; and that the other four were formed 

 *' each of its two neighbours ; that is, the orange from the red and yellow, the green from 

 *' the yellow and blue, the indigo from the blue and violet, and the violet from the red 

 « and indigo. But this fuppofition has never been proved." See his Philofophy of Chcm. 



Vol. IV, — December 1800. 3 D cKap, 



